The long-term objective of this proposal is to study the role intersensory integration plays in learning and memory processes in human infants, to determine the functional significance of this role, and examine how this role changes across development. To begin this process, the current proposal will examine how human infants use intersensory information (visual and haptic) about the shape of an object to influence learning and retention of an operant response. To accomplish this, a new procedure will be developed that combines haptic exploration of an object with learning an operant response-that leg kicks move a toy mobile. Learning and retention of the operant response will be assessed as a function of the similarity between the shape of the object held (haptic information) and the shape of the mobile objects (visual information). Kicking rates and measures of haptic exploration will serve as dependent measures. Two primary hypotheses will be tested. First, will detection of the cross-modal correspondence of shape facilitate learning and/or retention of an operant learning task? Second, will this facilitation be age-dependent? Intersensory interactions are not a unitary phenomenon and numerous age-related differences have been reported. Infants'behavioral responses depend on the type of correspondence, the task, the modalities involved, and the developmental level of the infant. Two age groups will be tested (3- and 5-month-old infants) to begin a preliminary study of age-related differences. In addition, establishment of this procedure as a valid and reliable method of examining intersensory interactions during infancy will aid our understanding of normal development as well as potentially providing an assessment tool to aid in the detection of developmental disabilities during the first half-year of life. This project will promote increased understanding of basic learning processes in human infants. The knowledge gained in understanding normal infant learning will help us, in turn, to identify those infants who show delayed/different patterns of learning. The ability to identify such patterns in infancy, rather than in early childhood, will allow for earlier intervention for those children at risk for developmental learning disabilities.